I found this interesting article. It's an experiment on a fly model, but at least the models used are models with alpha-synuclein induced PD. The conclusion is that even decafeinated coffee and nicotine free tobacco has neuroprotective effects. So there are chemicals in coffee and tobacco other than cafein and nicotine that are neuroprotective.
I read several stories of this and I advised my father to drink coffee without milk. The milk is supposed to interact with some of the chemicals that are beneficial for the brain.